This research investigated the relationship between fuel poverty and carbon monoxide (CO) risk in households on low incomes and in vulnerable situations. Over the course of two heating seasons (October to April) in 2015/16 and 2016/17 NEA collected data from 349 households, targeting those on low incomes and with a range of vulnerabilities. The main conclusion to draw from this research is that the factors which cause or expose households to the risk of fuel poverty – low income, poor quality housing and the age and health of occupants – can impact on the heating and servicing behaviours of households to elevate CO risk in homes.